A theoretical study about excited state behaviour for imide compound N-cyclohexyl-3-hydroxyphthalimide and 3,6-dihydroxy-N-cyclohexylphthalimide

摘要

In this present work, adopting density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, we theoretically research the excited state dynamical process about two imide compound N-cyclohexyl-3-hydroxyphthalimide (3HNHPI) and 3,6-Dihydroxy-N-cyclohexylphthalimide (DHNHPI). We find the intramolecular hydrogen bonds in these two systems should be strengthening in the S-1 state, which may trigger excited state intramolecular proton transfer (ESIPT) reaction. Analysis about charge redistribution implies the tendency of ESIPT reaction for both 3HNHPI and DHNHPI. However the constructed potential energy surfaces confirm that the ESIPT process should occur for 3HNHPI rather than DHNHPI molecule, which is consistent with previous experiment [Phys. Chem. Chem. Phys. 17 (2015) 30659-30669]. Via transition state (TS) theory, we successfully account for the vague explanation in previous work and clarify that why the proton transfer reaction missing for DHNHPI in the S-1 state. (C) 2017 Elsevier B.V. All rights reserved.